if you only have a point and slop you would use the formula- y-y1 = m(x-x1)
with your number the equation would be y-6 = 1/4(x+8)
the eight became a positive because in the equation the x is negative and a negative times a negative is a positive*
you would the solve the equation to be in y=mx+b form and it would be
y=1/4x +8
i hope this helped